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Biomedical subjects

G S Beaudreau

Publications and source records attributed to G S Beaudreau.

At least 37 records · Page 2Linked to original sources
PubMed1979

Tryptic peptide analysis and NH2-terminal amino acid sequences of polyhedrins of two baculoviruses from Orgyia pseudotsugata.

Comparative analysis of the tryptic peptides and terminal amino acid sequence was made on polyhedrins from two genetically different baculoviruses that are naturally pathogenic for the same insect host. Comparison of the tryptic peptides of the nucleopolyhedrosis bundle virus and nucleopolyhedrosis single-rod virus of Orgyia pseudotsugata by means of cation-exchange resins indicated that the proteins have a closely related amino acid sequence. The NH(2)-terminal amino acid sequence of polyhedrins from the two viruses differed in only 4 out of 34 amino acids. The nucleopolyhedrosis bundle virus and the nucleopolyhedrosis single-rod virus also differed in 4 and 5 out of 34 terminal amino acids, respectively, from the sequence reported for polyhedrin of a baculovirus of Bombyx mori [Serebryani, S. B., Levitina, T. L., Kautsman, M. L., Radavski, Y. L., Gusak, N. M., Ovander, M. N., Sucharenko, N. V. & Kozlov, E. A. (1977) J. Invertebr. Pathol. 30, 442-443]. In addition, the nucleopolyhedrosis single-rod virus had two amino acids (Met-Tyr) on the NH(2) terminus that were not present on the terminus of nucleopolyhedrosis bundle virus or B. mori baculovirus polyhedrin. Approximately half (six) of the total tyrosine residues are clustered in the terminal 20 amino acids of the polyhedrins. Secondary structures predicted from the primary sequence suggest that the tyrosines are clustered in two areas. This nonrandom distribution and the pK(a) of about 10 for tyrosine may be related to the alkali solubility of the polyhedrin.

Amino Acid Sequence↗
PubMed1978

Quantification of two viruses in technical preparations of Orgyia pseudotsugata baculovirus by means of buoyant density centrifugation of viral deoxyribonucleic acid.

A reliable method was developed for the quantitative determination of two nuclear polyhcdrosis viruses present in commercially prepared viral insecticides used against Orgyia pseudotsugata. Deoxyribonucleic acids, from nuclear polyhedrosis bundle virus and nuclear polyhedrosis single-rod virus, were separated on CsCl gradients according to their respective buoyant densities, 1.715 and 1.704 g/ml. The proportions of the two viruses were quantified by measuring the relative absorbance at 254 nm of their deoxyribonucleic acid peaks.

Animals↗
PubMed1977

Measurement of proviral genes in uninfected and avian myeloblastosis virus-infected cells by hybridization with 3H-labeled complementary DNA probe excess.

Viral RNA (vRNA) from avian myeloblastosis virus or DNA from virus-infected and uninfected cells was hybridized with [3H]DNA complementary to viral RNA ([3H]cDNA) under conditions of [3H]cDNA excess. When [3H]cDNA was used to drive the hybridization reaction with vRNA, a rate constant of 33.2 liters/mol-s was obtained. The same rate constant was obtained when vRNA excess was used as the driver. The specific activities of the [3H]DNA probe, estimated from kinetic measurements of the hybridization reaction and from the amount of [3H]cDNA in hybrid form at equilibrium, were 9.1 and 8.6 cpm/pg, respectively. DNA isolated from uninfected cells contained five or six copies of proviral DNA per cell genome. DNA isolated from erythrocytes infected with avian myeloblastosis virus had an additional five or six viral genes added to the cell genome, and the virus-infected target cell (myeloblasts) contained about 15 additional copies of proviral DNA per cell. The use of excess [3H]cDNA probe is an easy and accurate method to quantify the frequency of proviral DNA sequences in cell DNA and to measure a small amount (40 to 200 pg) of vRNA. Probe excess hybridization offers a number of advantages over other procedures and these are discussed.

Animals↗
PubMed1976

Identification of DNA in the core component of avian myeloblastosis virus.

Avian myeloblastosis virus (AMV) was found to contain DNA associated with the virion. The viral envelope was removed by treating the virus with a nonionic detergent and the DNA was found in the core fraction. These experiments indicate that the DNA associated with tumor virus is not contaminant associated with the viral envelope and suggest that the DNA is part of the internal core component. The DNA from avian myeloblastosis virus has a density of 1.70 g/cm3.

Avian Leukosis Virus↗
PubMed1976

Analysis of subunit organization in chicken erythrocyte chromatin.

Micrococcal nuclease digestion of intact chicken erythrocyte nuclei is shown to result in the formation of core nucleoprotein particles containing about 140 base pairs of DNA. These core particles, which are almost entirely devoid of histones f1 and f2c, are derived from transient nucleoprotein particles containing an average of approximately 180 base pairs of DNA. Oligomers of these latter particles may be isolated after brief nuclease digestion. The time course of digestion of these oligomers demonstrates the existence of "spacer" regions of more accessible DNA between core particles. Redigestion of purified monomer core nucleoprotein particles gives rise to both single-strand and double-strand DNA fragment patterns similar to those resulting from digestions of chromatin in situ. This observation indicates that the core particles we isolate are representative of nucleoprotein structures existing within the nucleus.

Animals↗
PubMed1976

Virus-infected avian cell lines established in vitro.

Four virus-infected avian cell lines have been established in culture. Two of these lines, infected with BAI strain A virus, liberate only small quantities of virus in the culture fluid. The cells retain the ability to induce myeloblastic leukemia when inoculated i.v. into 1- to 2-day-old chicks, but do so less efficiently than freshly obtained myeloblasts. These cells do not appear to be transplantable, since the disease produced is characterized by the presence of myeloblasts that liberate large quantities of virus. The other two cell lines, infected with the MC29 strain of avian leukosis virus, liberate normal levels of infectious virus in the culture fluid. When these cells are inoculated into the wing web of 1- to 2-day-old chicks, tumors develop at the site of inoculation which are detectable as early as 4 to 7 days after challenge. Chromosome studies demonstrate that the four cell lines have karyotypes typical of Gallus domesticus. The myeloblastic cell lines (D.U. 11157 and D.U. 1765) show a reduction in the number of microchromosomes. These cell lines have been carried in continuous culture for various lengths of time, can be frozen, are easily recovered in viable form, and appear to be capable of indefinite growth.

Adenosine Triphosphatases↗
PubMed1974

Visualization of single-stranded nucleic acid of RNA tumor virus with the electron microscope.

60-70S RNA of avian myeloblastosis virus was spread with the Kleinschmidt method and examined in the electron microscope after being subjected to a variety of denaturing conditions. Extension of the molecules from a collapsed configuration was seen only under stringent denaturing conditions, resulting in molecules of 1-2 mum in length. Longer strands of these extremely fragile molecules cannot be obtained with the methods presently available.

Avian Leukosis Virus↗
PubMed1971

Deoxyribonucleic acid polymerase activity associated with strain MC29 tumor virus.

Chick embryo cells infected with strain MC29 tumor virus yielded progeny virus that contained detectable deoxyribonucleic acid (DNA) polymerase within the first 48 hr after infection. The noninfected culture fluids displayed no such enzyme activity when examined in an identical manner. Enzyme activity was greatly stimulated by adding DNA template to the reaction mixture and required all four deoxyribonucleoside triphosphates for full activity. When calf thymus DNA was used to direct synthesis, the DNA polymerase from the MC29 virus catalyzed the formation of DNA product having a higher buoyant density in CsCl. DNA product formed in the reaction directed by Micrococcus lysodeikticus DNA had the same buoyant density as the template DNA.

Animals↗
PubMed1971

Deoxyribonucleic acid polymerase activity associated with a plasma particulate fraction from patients with chronic lymphocytic leukemia.

Plasma from two cases of chronic lymphocytic leukemia have been examined for deoxyribonucleic acid (DNA) polymerase activity. In both cases, detectable enzyme activity was present. In the plasma from a patient known to have chronic lymphocytic leukemia for 10 years, the enzyme activity was sufficiently high to study product formation, buoyant density of the enzyme activity, deoxyribonucleoside triphosphate requirements, and kinetics of DNA synthesis. These studies are presented in this report.

Aged↗